"FrankenBrakes" power booster

[srgould41]

What is your current setup exactly?

I've got hydroboost in my rig. The hydroboost unit replaces only the vacuum booster. You still use a regular hydraulic brake master cylinder, with or without a proportioning valve as you prefer.

I never ran the 4Runner calipers with hydroboost, but I did run the stock FJ60 front calipers with FZJ80 rear calipers and she stopped well with 37s. No comparison to how she stops now, but it was good.

 

[GLTHFJ60]

What is your current setup exactly?

Dana 60 dually calipers up front, 14 bolt disk brakes out back with a MC out of a 70s vette IIRC and Hydroboost. She stops 11k# roughly as well as the stock brakes stopped the stock truck with camping gear in it

Not exactly a bolt-on mod in my case though.

 

[srgould41]

Ah... Got it. One Tons. Can't really compare to stock axles and brakes, huh

Dana 60 dually calipers up front, 14 bolt disk brakes out back with a MC out of a 70s vette IIRC and Hydroboost. She stops 11k# roughly as well as the stock brakes stopped the stock truck with camping gear in it

Not exactly a bolt-on mod in my case though.

 

[GLTHFJ60]

Ah... Got it. One Tons. Can't really compare to stock axles and brakes, huh

Exactly.

In reality the hydroboost alone won't make that much of a difference to the brake system. It may change the pedal feel a bit by allowing you to put more pressure on the MC pushrod, but the overall system function is going to be made by matching the MC to the caliper. The advantages are that you don't need a big vacuum line running to the booster and that the booster itself is smaller. The disadvantage is that you now need a PS reservoir with two return fittings, and an extra high pressure line.

 

[srgould41]

It WILL make a big difference to the brake system if you are like me, running a smaller diameter master to provide sufficient brake line pressure to stop. HB is on my list once I have replaced all my soft and hard lines. 40 year old hard lines worry me as it is. Adding even higher pressure maybe isn't a good idea on them old lines

Exactly.

In reality the hydroboost alone won't make that much of a difference to the brake system. It may change the pedal feel a bit by allowing you to put more pressure on the MC pushrod, but the overall system function is going to be made by matching the MC to the caliper. The advantages are that you don't need a big vacuum line running to the booster and that the booster itself is smaller. The disadvantage is that you now need a PS reservoir with two return fittings, and an extra high pressure line.

 

[offrd63]

I guess my next step should be to hook up my vacuum qauge and see were I'm at

 

[srgould41]

It's nice to know how much vacuum you have to work with, but there really isn't anything you can do about it. When I bought my booster the docs said 18" minimum. With 14" at idle I know I'm not getting the most assist the unit can provide so I went with the largest I could find to make up for the low vac. Staying with Toyota parts you don't have as much choice. I have not seen any posts comparing assist levels between, say a dual diaphragm from a truck versus an FJ80. I'd say just make sure it is a dual diaphragm (sticks way out from firewall) and can fit.

Now what I would like to see is someone make a triple diaphragm booster, dual mounted inline with a single.

 

[offrd63]

It's nice to know how much vacuum you have to work with, but there really isn't anything you can do about it. When I bought my booster the docs said 18" minimum. With 14" at idle I know I'm not getting the most assist the unit can provide so I went with the largest I could find to make up for the low vac. Staying with Toyota parts you don't have as much choice. I have not seen any posts comparing assist levels between, say a dual diaphragm from a truck versus an FJ80. I'd say just make sure it is a dual diaphragm (sticks way out from firewall) and can fit.

Now what I would like to see is someone make a triple diaphragm booster, dual mounted inline with a single.

My number is 12". That's it, 12in.HD vac. I wish now that I had a base line to refer to. I could have, I've certainly been lurking here long enough to have known.
This project has had me searching the archives a lot. I have been reading old posts this week, on this same topic from many of you that are commenting now, and it made me think of the old days when woody and others that are still here would often post up.
I started a full resto in 1998, when my only sources were Specter, and Cruiser Outfitters in SLC. Then I tore it all up and started changing things in Feb. 2002 after being introduced to Mud. Historically this is where someone would chirp up and say "search", or "Take it to chat",LOL It's nice to be able to "chat," and build with like minded people.

Thanks all

aw

 

[srgould41]

Any updates on your brakes?

I plan to replace all my plumbing this winter, hard and soft lines both. I decided to go forward with hydroboost. I just bought a booster from a wrecked 3/4 ton Chevy. Should arrive soon. Then lots of work and money to get it all installed.

My number is 12". That's it, 12in.HD vac. I wish now that I had a base line to refer to. I could have, I've certainly been lurking here long enough to have known.
This project has had me searching the archives a lot. I have been reading old posts this week, on this same topic from many of you that are commenting now, and it made me think of the old days when woody and others that are still here would often post up.
I started a full resto in 1998, when my only sources were Specter, and Cruiser Outfitters in SLC. Then I tore it all up and started changing things in Feb. 2002 after being introduced to Mud. Historically this is where someone would chirp up and say "search", or "Take it to chat",LOL It's nice to be able to "chat," and build with like minded people.

Thanks all

aw